Design and test of a new tracheostoma valve based on inhalation

Background: Tracheostoma valves are used to make hand-free speaking possibl e for persons who have undergone a laryngectomy. Objective: To design and test a new tracheostoma valve to improve existing tracheostoma valves. Methods: The tracheostoma valve closes by means of strong inhalation so tha t all the air that is exhaled is available for phonation. The device automa tically stays in the "speaking position" until the patient deliberately cha nges the device to the "breathing position" by a fast expiration. If all th e air that has been exhaled has been consumed during phonation, the patient can inhale again, without changing the device, because a small valve autom atically opens, thus allowing phonation without time limits. An experimenta l setup with a computer-based acquisition program was used to measure the p ressure at which the valve opened and the flow at which the valve closed. T he pressure and flow needed to open and close the magnetic adjustable valve were measured for different positions and contained in the computer throug h a data acquisition program. Also, the airflow resistance coefficients for inhaling and exhaling were measured. Results: The airflow necessary to close the tracheostoma valve ranges from 1.6 to 3.8 Us. The opening pressure of the valve ranges from 1 to 7 kPa. Th e airflow resistance coefficient is 290 Pa . s(2) . L-2 for inhalation and 430 Pa . s(2) . L-2 for er;halation. Conclusions: The device appears to function well in physiological ranges an d is optimally adjustable. The airflow resistance coefficient lies in the r ange of the entire airway resistance (120-470 Pa . s(2) . L-2) in quiet bre athing.